The present invention involves utilization of two major principles, these being (A) the “blowerless” principle, which is the use of exhaust energy to draw air into the combustion cylinder, and (B) the retro-flow principle which is a reverse flow of air back through an exhaust outlet tube and into the cylinder.
Historically, the blowerless principle has been used in experimental engines as the sole source of scavenging air. Other two-stroke engines also now use the principle, but only to augment the pressure difference. The retro-flow principle, so far as can be determined, has not heretofore been discovered and exploited.
Heretofore, there have been many attempts to design and provide a two, stroke engine which is not dependent for its combustion air upon crankcase air pumping or a blower. Although certain of these attempts have succeeded, in each case the engine speed range was quite limited, and long bulky pipes were required to provide air intake.